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Abstract:

Keyboard systems for interfacing with a touchscreen. The keyboard
includes: a plurality of contact members formed of electrically
conducting material, each of the contact members having first and second
sides; and a plurality of keys. Each key has an electrically conducting
key-pad unit and a resilient member, where the resilient member is
adapted to maintain the key-pad unit in a spaced part relationship
relative to a corresponding one of the contact members. The first side of
each contact member is in constant contact with a particular portion of
the touchscreen. The key-pad unit is adapted to contact the second side
of a corresponding one of the contact members when pressed by a foreign
object, to thereby form an electrically conducting path between the
foreign object and the particular portion of the touchscreen.

Claims:

1. A keyboard system for interfacing with a touchscreen, comprising: a
plurality of contact members formed of an electrically conducting
material, each said contact member having first and second sides; and a
plurality of keys, each said key having an electrically conducting
key-pad unit and a resilient member, said resilient member being adapted
to maintain the key-pad unit in a spaced part relationship relative to a
corresponding one of said plurality of contact members; wherein the first
side of each said contact member is in constant contact with a particular
portion of the touchscreen; and wherein the key-pad unit is adapted to
contact the second side of a corresponding one of said plurality of
contact members when pressed by a foreign object, to thereby form an
electrically conducting path between the foreign object and the
particular portion of the touchscreen.

2. A keyboard system as recited in claim 1, wherein the key-pad unit
includes at least one of a key-pad disk and a key-pad ring formed of an
electrically conducting material.

3. A keyboard system as recited in claim 2, wherein the key-pad disk has
a substantially circular, oval, or polygon shape.

4. A keyboard system as recited in claim 2, wherein the key-pad ring has
a substantially circular, oval, or polygon shape.

5. A keyboard system as recited in claim 2, wherein the key-pad ring is
formed on a portion of a top surface of the key-pad disk, a portion of a
bottom surface of the key-pad disk, and a portion of a side of the
key-pad disk.

6. A keyboard system as recited in claim 1, wherein the key-pad unit
includes one or more key-pad disks connected to one or more vias, the
key-pad disks and the vias are formed of an electrically conducting
material.

7. A keyboard system as recited in claim 1, wherein each said contact
member includes a bump formed on the first side and in constant contact
with the particular portion of the touchscreen.

8. A keyboard system as recited in claim 1, further comprising: a first
panel formed of a dielectric material, wherein the plurality of contact
members are secured to the first panel.

9. A keyboard system as recited in claim 8, further comprising: a second
panel formed of a dielectric material, wherein the plurality of keys are
secured to the second panel.

10. A keyboard system as recited in claim 1, wherein the keyboard system
is slidably mounted to a touchscreen.

11. A keyboard system as recited in claim 1, wherein the keyboard system
is rotatably mounted to a touchscreen.

12. A keyboard system as recited in claim 1, wherein the key-pad unit
includes a key-pad disk formed of a transparent material so that a user
is able to see the particular portion of the touchscreen therethrough.

13. An electronic device, comprising: a touchscreen; a keyboard system
for interfacing with the touchscreen, said keyboard system including: a
plurality of contact members formed of an electrically conducting
material and having first and second sides; and a plurality of keys, each
said key having an electrically conducting key-pad unit and a resilient
member, said resilient member being adapted to maintain the key-pad unit
in a spaced part relationship relative to a corresponding one of said
plurality of contact members; wherein the first side of each said contact
member is in constant contact with a particular portion of the
touchscreen; and wherein the key-pad unit is adapted to contact the
second side of a corresponding one of said plurality of contact members
when pressed by a foreign object, to thereby form an electrically
conducting path between the foreign object and the particular portion of
the touchscreen.

14. An electronic device as recited in claim 13, wherein the key-pad unit
includes at least one of a key-pad disk and a key-pad ring formed of an
electrically conducting material.

15. An electronic device as recited in claim 13, wherein the key-pad unit
includes one or more key-pad disks connected to one or more vias, the
key-pad disks and the vias are formed of an electrically conducting
material.

16. An electronic device as recited in claim 13, wherein each said
contact member includes a bump formed on the first side and in constant
contact with the particular portion of the touchscreen.

17. An electronic device as recited in claim 13, further comprising: a
first panel formed of a dielectric material, wherein the plurality of
contact members are secured to the first panel.

18. An electronic device as recited in claim 17, further comprising: a
second panel formed of a dielectric material, wherein the plurality of
keys are secured to the second panel.

19. An electronic device as recited in claim 13, wherein the keyboard
system is rotatably mounted to a touchscreen.

20. An electronic device as recited in claim 13, wherein the key-pad unit
includes a key-pad disk formed of a transparent material so that a user
is able to see the particular portion of the touchscreen therethrough.

Description:

BACKGROUND OF THE INVENTION

[0001] The present invention relates to data entry keyboards, and more
particularly, to tactile keyboards for touch screen.

[0002] With the advancement of electronic technologies, touchscreens have
become increasingly popular in the field of consumer electronics. A
touchscreen is a display capable of detecting the presence and location
of a touch (or stimulus) within a display area and interpreting the touch
as input. The ability of a touchscreen to receive (i.e., detect and
interpret) a stimulus is typically enabled through the use of a plurality
of touch-sensitive sensors embedded in the touchscreen.

[0003] Touch-sensitive sensors respond to a stimulus and produce a signal
indicative of the stimulus's magnitude, relative position, or other
characteristic attributable to the stimulus. Typical touch-sensitive
sensor implementations in the field of consumer electronics include
resistive sensing, capacitive sensing, infrared sensing, optical imaging
and dispersive signal technology.

[0004] Applications in which touchscreen applications may be used include
display interfaces of computing devices, such as notebook computers,
iPad® tablet computer, personal data assistants (PDAs), and mobile
phones. Other popular applications in which touchscreens have been
incorporated include the user interfaces of bank automated telling
machines, kitchen appliances, exercise equipment, satellite navigation
devices and various other consumer electronics.

[0005] Displays which offer touchscreen functionality provide substantial
benefits over traditional displays. These benefits include the ability to
directly interact with the content displayed on the touchscreen, rather
than indirectly with a dedicated input device, such as a keyboard,
keypad, mouse, or touchpad. Another benefit of a touchscreen display is
the ability to receive input without requiring the presence of a
dedicated input device. As consumer electronic devices (particularly
mobile handsets) continue to reduce in size, the inclusion of a
touchscreen provides a manufacturer the ability to further reduce the
size of the device by eliminating the space required for an input
terminal. In addition, by devoting the entirety of a device's surface
area for use as a display rather than apportioning the surface area
between a display area and an input terminal (e.g., keypad), the total
display area may be increased, resulting in a superior user experience.

[0006] However, in general, mobile computing devices such as cell phones,
smart phones and PDAs which use touchscreens as a primary method of input
may be difficult or inconvenient to use. For example, typical
touchscreens lack the tactile feedback provided by pressing a tangible
button or key in a physical input terminal. Accordingly, users may be
uncertain whether any key was actuated at all or any key was actuated
more times than intended. Thus, in order for the user to be assured that
input is being received as intended, the user is required to monitor the
output field on the display to verify both that a key was entered, and
more specifically, that the correct key was entered as intended.

[0007] Since data entry into the conventional touchscreen is simply based
on the 2-D virtual keypad displayed on the monitor, the virtual keys are
without depth or any feel other than the simple pressure reaction by the
flat surface, and the user must therefore carefully aim to touch the
desired virtual key. Unlike the conventional remote keyboard, the
touchscreeen has no capability to provide tactile feedback to the user,
which limits its usefulness and accuracy in use. Accordingly, it is
desired to provide tactile feedback in a touch screen for matching the
benefits of a mechanical keyboard.

SUMMARY OF THE INVENTION

[0008] In one embodiment of the present disclosure, a keyboard system for
interfacing with a touchscreen includes: a plurality of contact members
formed of electrically conducting material, each of the contact members
having first and second sides; and a plurality of keys. Each key has an
electrically conducting key-pad unit and a resilient member, where the
resilient member is adapted to maintain the key-pad unit in a spaced part
relationship relative to the corresponding contact member. The first side
of each contact member is in constant contact with a particular portion
of the touchscreen. The key-pad unit is adapted to contact the second
side of the corresponding contact member when pressed by a foreign
object, to thereby form an electrically conducting path between the
foreign object and the particular portion of the touchscreen thorough the
contact members and the electrically conducting key-pad unit.

[0009] In another embodiment of the present disclosure, an electronic
device includes a touchscreen and a keyboard system to be mounted on the
touchscreeen. The keyboard system includes: a plurality of contact
members formed of electrically conducting material, each of the contact
members having first and second sides; and a plurality of keys. Each key
has an electrically conducting key-pad unit and a resilient member, where
the resilient member is adapted to maintain the key-pad unit in a spaced
part relationship relative to a corresponding one of the contact members.
The first side of each contact member is in constant contact with a
particular portion of the touchscreen. The key-pad unit is adapted to
contact the second side of a corresponding one of the contact members
when pressed by a foreign object, to thereby form an electrically
conducting path between the foreign object and the particular portion of
the touchscreen thorough the contact members and the electrically
conducting key-pad unit.

[0010] These and other features, aspects and advantages of the present
invention will become better understood with reference to the following
drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows an exploded view of a keyboard system disposed over a
portion of a touchscreen in accordance with one embodiment of the present
invention;

[0012]FIG. 2 shows a top view of a portion of the keyboard system of FIG.
1;

[0013]FIG. 3A shows a cross sectional view of the portion of the keyboard
system in FIG. 2, taken along the line 3-3;

[0014]FIG. 3B shows a cross sectional view of the portion of the keyboard
system in FIG. 2, illustrating the key action when a finger presses the
key;

[0015] FIG. 4A shows a top view of a contact member in accordance with
another embodiment of the present invention;

[0020] FIG. 5 shows a cross sectional view of a portion of a keyboard
system having the contact member of FIG. 4A;

[0021]FIG. 6 shows a top view of a portion of a keyboard system in
accordance with yet another embodiment of the present invention;

[0022]FIG. 7 shows a cross sectional view of the portion of the keyboard
system in FIG. 6, taken along the line 7-7; and

[0023] FIG. 8 shows a cross sectional view of a portion of a keyboard
system in accordance with still another embodiment of the present
invention;

[0024]FIG. 9A shows a top view of a portion of a keyboard system in
accordance with further another embodiment of the present invention;

[0025]FIG. 9B shows a cross sectional view of the portion of the keyboard
system of FIG. 9A, taken along the line 9-9;

[0026]FIG. 10 shows a cross sectional view of a portion of a keyboard
system in accordance with yet further another embodiment of the present
invention;

[0027]FIG. 11 shows a cross sectional view of a portion of a keyboard
system in accordance with another embodiment of the present invention;

[0028]FIG. 12A shows a side view of a keyboard system rotatably attached
to an electronic device or device case in accordance with still further
another embodiment of the present invention;

[0029]FIG. 12B shows a side view of the keyboard system of FIG. 12A
disposed over the touchscreen of the electronic device when being used;

[0030]FIG. 12c shows a side view of the keyboard system of FIG. 12A
retracted under the electronic device when not used;

[0031]FIG. 13A shows a perspective view of a keyboard system slidably
mounted to an electronic device in accordance with another embodiment of
the present invention;

[0032]FIG. 13B shows a front view of the keyboard system of FIG. 13A
disposed over the touchscreen of the electronic device when being used;

[0033]FIG. 13c shows a front view of the keyboard system of FIG. 13A
stowed under the electronic device when not used; and

[0034]FIG. 14 shows a front view of a keyboard system slidably mounted to
an electronic device in accordance with another embodiment of the present
invention.

DETAILED DESCRIPTION OF THE INVENTION

[0035] Referring now to FIG. 1, there is shown an exploded view of a
keyboard system 11 to be disposed over a portion of a touchscreen 12 in
accordance with one embodiment of the present invention. As depicted, a
device 10 may be a conventional electronic device and includes the
touchscreen 12 for displaying various digital images. The touchscreen 12
includes touch-sensitive sensors (not shown in FIG. 1) embedded therein,
where the sensor implementation includes capacitive sensing technology.
For the purpose of illustration, the sensors in the touchscreen 12 are
considered to be capacitive sensors, even though other suitable type of
sensors may be used in the touchscreen 12.

[0036] The touch-sensitive sensors are responsive to a physical stimulus
or contact with a foreign object, such as finger or stylus. Thus, when an
image including virtual keys 14 is displayed on the touchscreen 12, the
user may input data to the device 10 by directly touching the virtual
keys 14. Since the virtual keys 14 are displayed on 2-D touchscreen, the
virtual keys 14 do not have depth or any feel other than the simple
pressure reaction atop the flat touchscreen 12. Thus, the user may mount
the keyboard system 11 on the touchscreen 12 so that the user can get
tactile feedback when inputting data into the device 10.

[0037] The keyboard system 11 includes: a lower keyboard unit 16 having a
lower panel 17 and a plurality of contact members 18 mounted in the lower
panel 17; and an upper keyboard unit 20 having an upper panel 21 and a
plurality of keys 22. When the keyboard system 11 is mounted on the
touchscreen 12, the lower keyboard unit 16 makes a firm contact with the
touchsreen surface. The lower panel 17 is formed of electrically
insulating (or, equivalently, dielectric) material, such as rubber or
plastic. The width and length of the lower panel 17 may be determined
such that the lower keyboard unit 16 covers the entire image of the
virtual keys 14. The contact members 18 are formed of electrically
conducting material, such as metal, carbon-filled rubber, carbon-filled
polymer, metal-filled rubber, metal-filled polymer. Each of the contact
members 18 has a substantially circular ring shape and is disposed over
the corresponding virtual key when the lower keyboard unit 16 is mounted
over the touchscreen 12. The location and diameter of each contact member
18 are determined such that the character (or symbol) of the
corresponding virtual key can be visible to the user through the inner
hole of the contact member.

[0038]FIG. 2 shows a top view of a portion of the keyboard system 11.
FIG. 3A shows a cross section view of the portion of the keyboard system
in FIG. 2, taken along the line 3-3. As depicted, the lower panel 17 and
contact members 18 are in firm contact with the touchscreen 12 when the
keyboard system 11 is mounted on the touchscreen 12. The upper panel 21
of the upper keyboard unit 20 is in contact with the lower panel 17. The
key 22 includes: a dome 24 (or, equivalently, spring member or resilient
member); a key-pad ring 26; and a key-pad disk 28 secured to the key-pad
ring 26. (A term key-pad unit collectively refers to the key-pad ring and
key-pad disk.) The upper panel 21 may be formed of electrically
insulating (or, equivalently, dielectric) material, such as silicone
rubber or other elastomer. The dome 24 may be formed of a dielectric
elastic material, such as silicone rubber or other elastomer, and
configured to separate the key-pad ring 26 from the contact member 18
when the key-pad disk 28 is not pressed by a finger.

[0039] The key-pad ring 26 is formed of an electrically conducting
material, such as metal, carbon-filled rubber, carbon-filled polymer,
metal-filled rubber, metal-filled polymer. The key-pad disk 28 may be
formed of a transparent material, such as polycarbonate or acrylic. The
upper keyboard unit 20 is arranged relative to the lower keyboard unit 16
such that the user may see the character (or symbol, say "A") displayed
on the corresponding virtual key 14 through the transparent key-pad disk
28 and the inner hole of the contact member 18.

[0040]FIG. 3B shows a cross section view of the portion of the keyboard
system in FIG. 2, illustrating the key action when a finger presses the
key 22. When the user presses the key 22, more specifically the key-pad
disk 28, the dome 24 flexes and bends to make a contact between the
key-pad ring 26 and the contact member 18. Since the dome 24 is formed of
elastic material, the deformed dome generates a resilient force so that
the key 22 restores to its original position (as shown in FIG. 3A) when
the user releases the key 22.

[0041] When the finger presses the key 22, the key-pad ring 26 makes a
physical contact with the contact member 18. Thus, even though the
virtual key 14 of the touchscreeen 12 is not directly activated by a user
finger, the virtual key 14 is activated by bringing the indirect contact
between the finger and the virtual key 14 via the key-pad ring 26, and
the contact member 18. More specifically, the capacitance of the finger
is transmitted to the virtual key 14 via the key-pad ring 26, and the
contact member 18. Thus, key-pad ring 26 and the contact member 18 form
an electrical path between the finger and virtual key 14.

[0042] While the touchscreen contact is the same as if a user had directly
placed his or her finger on the touchscreen 12, the sensation to the user
has been altered since the user can now feel the sensation of physical
displacement of the key-pad disk 28 as well as the key-pad displacement
arrested by contact with the contact member 18. Thus, the user receives a
tactile feedback signal, while the signal has been applied to the
touchscreen 12. The keyboard system 11 is a mechanical interface for the
touchscreen 12 and provides tactile feedback to the user. The key-pad
disk 28 may be eliminated depending on the design implementation.

[0043] As shown in FIGS. 3A and 3B, the entire bottom surface of the
contact member 18 contacts the corresponding virtual key 14. As an
alternative, the actual contact area between the contact member 18 and
the virtual key 14 may be modified so that the contact can more closely
simulate a finger touch. FIGS. 4A-4E respectively show a top view, a
bottom view, a side view, a front view, and a bottom perspective view of
a contact member 30 in accordance with another embodiment of the present
invention. As depicted, the contact member 30 includes a protrusion (or
bump) 32 that makes a direct and constant contact with the corresponding
virtual key 14. FIG. 5 shows a cross section view of a portion of a
keyboard system having the contact member 30. As depicted, the keyboard
system is similar to the system 11 (shown in FIG. 1) with the difference
that the contact member 32 has a protrusion. The modification of the
contact area of the contact member serves to produce an input more
closely representing the touch of a finger, which the device is designed
to recognize. This eliminates erroneous multi-activations. The bottom
surface of the protrusion 32 may be flush with the bottom surface of
lower panel 33, or may extend beyond the bottom surface of lower panel 33
to ensure a good contact with the virtual key 14.

[0044] The key 22 may have other geometrical shapes. FIG. 6 shows a top
view of a portion of a keyboard system in accordance with yet another
embodiment of the present invention. FIG. 7 shows a cross sectional view
of the portion of the keyboard system in FIG. 6, taken along the line
7-7. As depicted, the keyboard system of FIG. 6 is similar to that of
FIG. 2, with the difference that the key 40 has a substantially
rectangular shape. The keyboard system includes: an upper panel 41; a
dome 42 (or, equivalently, resilient or spring member); a key-pad ring 44
that has a substantially rectangular ring shape; a transparent key-pad
disk 46 secured to the key-pad ring 44; a lower panel 48; and a contact
member 50 that has a substantially rectangular ring shape. Since each of
the components of the keyboard system shown in FIG. 6 is similar to its
counterpart of the keyboard system 11 in FIGS. 1, 2, and 3A, the
description of the keyboard system in FIGS. 6-7 is not repeated.

[0045] FIG. 8 shows a cross section view of a portion of a keyboard system
in accordance with still another embodiment of the present invention. As
depicted, the keyboard system in FIG. 8 is similar to that of FIG. 7,
with the difference that the contact member 52 has a protrusion (or
equivalently, bump) 54. The function and structure of the protrusion is
similar to those of the protrusion 32 (shown in FIGS. 4A-4E).

[0046]FIG. 9A shows a top view of a portion of a keyboard system in
accordance with further another embodiment of the present invention. FIG.
9B shows a cross sectional view of the portion of the keyboard system of
FIG. 9A. As depicted, the upper keyboard unit includes an upper panel 60
and a key 62, where the key 62 includes a dome 64 (or, equivalently,
resilient member or spring member) and a key-pad disk 66. The key-pad
disk 66 is formed of opaque and electrically conducting material, such as
metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber,
metal-filled polymer. The key-pad disk 66 may include a character (say,
"A") that matches the corresponding virtual key displayed on the
touchscreen 12. Since the lower keyboard unit 65 is similar to the lower
keyboard unit 16, the description of the lower keyboard unit is not
repeated for brevity.

[0047] It is noted the key-pad disk 66 may be formed of transparent and
electrically conducting material, such as ITO (indium tin oxide). In this
embodiment, the user may see the characters displayed on the touchscreen
through the key-pad disks, and thus, the key-pad disk 66 may not include
any character that matches the corresponding virtual key displayed on the
touchscreen 12.

[0048]FIG. 10 shows a cross sectional view of a portion of a keyboard
system in accordance with yet further another embodiment of the present
invention. As depicted, the upper keyboard unit includes an upper panel
78 and a key 70, where the key 70 includes a dome 76 (or, equivalently,
resilient member or spring member) and a key-pad unit 71 having a pair of
key-pad disks 72a, 72b connected by vias 74. One of the key-pad disk 72a
or 72b may be eliminated as long as vias 74 can make good contact with
the finger or the contact member 73. The vias 74 are formed of
electrically conducting material, such as metal, carbon-filled rubber,
carbon-filled polymer, metal-filled rubber, metal-filled polymer, and
pass through the upper panel 78.

[0049] The key-pad disks 72a, 72b are formed of electrically conducting
material, such as metal, carbon-filled rubber, carbon-filled polymer,
metal-filled rubber, metal-filled polymer. When a finger of the user
presses the key-pad disk 72a to thereby bring the key-pad disk 72b into
contact with the contact member 73, the capacitance of the finger is
transmitted to the virtual key displayed on the touchscreen 12 through
the upper key-pad disk 72a, the vias 74, the lower key-pad disk 72b, and
the contact member 73. Since the lower keyboard unit is similar to the
lower keyboard unit in FIG. 9B, the description of the lower keyboard
unit is not repeated for brevity.

[0050]FIG. 11 shows a cross sectional view of a portion of a keyboard
system in accordance with another embodiment of the present invention. As
depicted, the upper keyboard unit includes an upper panel 96 and a key 90
where the key 90 includes a dome 94 (or, equivalently, resilient member
or spring member), a key-pad disk 92, and a key-pad ring 98. The key-pad
disk 92 is formed of transparent material, such as polycarbonate or
acrylic. The key-pad disk 92 is affixed to the dome 94. The key-pad ring
98 is formed of a thin electrically conductive material, such as metal,
carbon-filled rubber, carbon-filled polymer, metal-filled rubber,
metal-filled polymer.

[0051] The key-pad ring 98 makes a contact with the contact member 95 when
the key-pad disk 92 is pressed by a finger of the user. Upon contact, the
capacitance of the finger is transmitted to the virtual key displayed on
the touchscreen 12 via the key-pad ring 98 and the contact member 95. The
key-pad ring 98 may be formed on the surface of the key-pad disk 92 by
various methods. For example, the key-pad ring 98 may be deposited on the
key-pad disk 92 by the conventional chemical vapor deposition technique,
or any other suitable vapor deposition technique. In another example, the
key-pad ring 98 may be coated or printed on the key-pad disk 92. Since
the lower keyboard unit is similar to the lower keyboard unit in FIG. 9B,
the description of the lower keyboard unit is not repeated for brevity.

[0052] In each of FIGS. 2-11, the dome and upper panel are shown to form
one integral body. For example, the dome 24 and the upper panel 21 are
made from one sheet of dielectric panel. However, the dome may be
fabricated separately from the upper panel and affixed to the upper
panel, i.e., the dome 24 may be fabricated with the key 22 and secured to
the upper panel 21 subsequently.

[0053] It is noted that the contact members in FIGS. 9A-11 do not have
protrusion (or bump). However, it should be apparent to those of ordinary
skill that the contact member 32 (shown in FIGS. 4A-4E) may be used in
place of the contact members shown in FIGS. 9A-11. It is also noted that
the key-pad disks and key-pad rings shown in FIGS. 1-11 may have a
suitable geometry, such as circle, rectangle, or polygon.

[0054]FIG. 12A shows a side view of a keyboard system 101 rotatably
attached to an electronic device 100 or an electronic device case (not
shown in the figure) by a linkage 106 in accordance with another
embodiment of the present invention. As depicted, the keyboard system 101
includes an upper keyboard unit 104 and a lower keyboard unit 102. One
end of the linkage 106 is rotatably attached to the electronic device 100
or an electronic device case (not shown in the figure) while the other
end of the linkage 106 is rotatably attached to the keyboard system 101.

[0055]FIG. 12B shows a side view of the keyboard system 101, where the
keyboard is disposed over the touchscreen of the electronic device 100.
The user can interact with the device 100 by pressing the keys 108 in the
keyboard system 101. FIG. 12c shows a side view of the keyboard system
101, where the keyboard system 101 is retracted under the electronic
device or an electronic device case (not shown in the figure) when the
user does not use the keyboard system 101.

[0056]FIG. 13A shows a perspective view of a keyboard system 111 slidably
mounted to an electronic device 113 in accordance with another embodiment
of the present invention. FIG. 13B shows a front view of the keyboard
system 111 disposed over the touchscreen 117 of the electronic device 113
when being used. FIG. 13c shows a front view of the keyboard system 111
stored in a cavity 112 when not used. As depicted, the keyboard system
111 includes: an upper keyboard unit 115 having keys 116; and a lower
keyboard unit 114. The structures and functions of the upper and lower
keyboard units 115, 114 are similar to those of the upper and lower
keyboard units 20, 16, respectively, and thus the description of the
units are not repeated.

[0057] The upper keyboard unit 115 and the lower keyboard unit 114 can be
slidably mounted along the grooves 119 formed on the inner wall of a case
110 so that the user can use the keyboard system 111 to interact with the
electronic device 113. The case 110 may be formed of material, such as
plastic, that can provide mechanical strength to hold the keyboard system
111. The case 110 includes a cavity 112 where the keyboard system 111 can
be stored when not used, as depicted in FIG. 13c.

[0058]FIG. 14 shows a front view of a keyboard system 120 slidably
mounted to an electronic device 126 in accordance with another embodiment
of the present invention. As depicted, the keyboard system 120 includes:
an upper keyboard unit 122 having keys 123; and a lower keyboard unit
124. The structures and functions of the upper and lower keyboard units
122, 124 are similar to those of the upper and lower keyboard units 20,
16, respectively, and thus the description of the units are not repeated.

[0059] The upper keyboard unit 122 includes a panel that extends over the
side of the electronic device 126 and covers a portion of the bottom
surface of the electronic device so that the keyboard system 120 can be
slidably mounted over the touchscreen of the electronic device 126. The
keyboard system 120 can be slidably mounted under the electronic device
126 when the keyboard system 120 is not used.

[0060] It should be understood, of course, that the foregoing relates to
exemplary embodiments of the invention and that modifications may be made
without departing from the spirit and scope of the invention as set forth
in the following claims.